Malcolm Palmer, 62, turned on the mother of his three children after she became hooked on the violent Grand Theft Auto driving game.

He was forced to sleep on a sofa in their conservatory as Carol Cannom, 46, stayed up all night with the 37-inch plasma television screen she brought into their room for her all-night gaming sessions.

He would play on the computer until midnight, after which Ms Cannom would take over, regularly staying up until five or six in the morning, Lincoln Crown Court was told.

"Carol quickly became hooked. He was very unhappy about the amount of time she was playing on the PlayStation," said John Pini QC for the prosecution.

The court yesterday (Monday) heard how Palmer had also become convinced that she was having an affair, and went into a violent rage when she told him she wanted him to move out in November last year, threatening that he would never get to see their children again.

That evening he attacked her with two knives, inflicting 20 separate wounds to her upper chest. The murder was overhead by their son James, who called 999 before Palmer grabbed the phone and told emergency operators: "I'm sorry. I think I've killed her."

Defence lawyer Timothy Spencer QC told the court: "The genesis of this tragedy bizarrely lies with the purchase of the PlayStation."

Palmer, who is a retired Heathrow airport worker, admitted the murder and will be sentenced on Wednesday.